Material parametric optimisation of wing leading edge profile against soft body impact

2020 ◽  
pp. 1-11
Author(s):  
S. Kavitha Mol ◽  
A. Sadiq
Keyword(s):  
Leading Edge ◽  
Soft Body ◽  
Parametric Optimisation ◽  
Edge Profile

Influence of Turbine Blade Leading Edge Profile on Film Cooling With Shaped Holes

2017 ◽  
Author(s):  
Mingjie Zhang ◽  
Nian Wang ◽  
Andrew F. Chen ◽  
Je-Chin Han
Keyword(s):  
Turbine Blade ◽  
Film Cooling ◽  
Density Ratio ◽  
Leading Edge ◽  
Stagnation Line ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Edge Profile ◽  
Elliptical Cylinders ◽  
Blade Leading Edge

This paper presents the turbine blade leading edge model film cooling effectiveness with shaped holes, using the pressure sensitive paint (PSP) mass transfer analogy method. The effects of leading edge profile, coolant to mainstream density ratio and blowing ratio are studied. Computational simulations are performed using the realizable k-ε turbulence model. Effectiveness obtained by CFD simulations are compared with experiments. Three leading edge profiles, including one semi-cylinder and two semi-elliptical cylinders with an after body, are investigated. The ratios of major to minor axis of two semi-elliptical cylinders are 1.5 and 2.0, respectively. The leading edge has three rows of shaped holes. For the semi-cylinder model, shaped holes are located at 0 degrees (stagnation line) and ± 30 degrees. Row spacing between cooling holes and the distance between impingement plate and stagnation line are the same for three leading edge models. The coolant to mainstream density ratio varies from 1.0 to 1.5 and 2.0, and the blowing ratio varies from 0.5 to 1.0 and 1.5. Mainstream Reynolds number is about 100,900 based on the diameter of the leading edge cylinder, and the mainstream turbulence intensity is about 7%. The results provide an understanding of the effects of leading edge profile and on turbine blade leading edge region film cooling with shaped-hole designs.

Influence of Turbine Blade Leading Edge Profile on Film Cooling With Shaped Holes

2018 ◽  
Vol 10 (5) ◽  
Author(s):  
Mingjie Zhang ◽  
Nian Wang ◽  
Andrew F. Chen ◽  
Je-Chin Han
Keyword(s):  
Turbine Blade ◽  
Film Cooling ◽  
Density Ratio ◽  
Leading Edge ◽  
Stagnation Line ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Edge Profile ◽  
Elliptical Cylinders ◽  
Blade Leading Edge

This paper presents the turbine blade leading edge model film cooling effectiveness with shaped holes, using the pressure sensitive paint (PSP) mass transfer analogy method. The effects of leading edge profile, coolant to mainstream density ratio, and blowing ratio are studied. Computational simulations are performed using the realizable k–ɛ (RKE) turbulence model. Effectiveness obtained by computational fluid dynamics (CFD) simulations is compared with experiments. Three leading edge profiles, including one semicylinder and two semi-elliptical cylinders with an after body, are investigated. The ratios of major to minor axis of two semi-elliptical cylinders are 1.5 and 2.0, respectively. The leading edge has three rows of shaped holes. For the semicylinder model, shaped holes are located at 0 deg (stagnation line) and ±30 deg. Row spacing between cooling holes and the distance between impingement plate and stagnation line are the same for three leading edge models. The coolant to mainstream density ratio varies from 1.0 to 1.5 and 2.0, and the blowing ratio varies from 0.5 to 1.0 and 1.5. Mainstream Reynolds number is about 100,000 based on the diameter of the leading edge cylinder, and the mainstream turbulence intensity is about 7%. The results provide an understanding of the effects of leading edge profile on turbine blade leading edge region film cooling with shaped hole designs.

Numerical Investigation of Bionic Rudder With Leading-Edge Protuberances

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Hongtao Gao ◽  
Wencai Zhu
Keyword(s):  
Electron Microscopy ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Hydrodynamic Performance ◽  
Spanwise Direction ◽  
Flow Mechanism ◽  
Suction Surface ◽  
Edge Profile ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The duck's webbed feet are observed by using electron microscopy, and observations indicate that the edges of the webbed feet are the shape of protuberances. Therefore, the rudder with leading-edge protuberances is numerically studied in the present investigation. The rudder has a sinusoidal leading-edge profile along the spanwise direction. The hydrodynamic performance of rudder is analyzed under the influence of leading-edge protuberances. The present investigations are carried out at Re = 3.2 × 105 and 8 × 105. In the case of Re = 3.2 × 105, the curves of lift coefficient illustrate that the protuberant leading-edge scarcely affects the lift coefficient of bionic rudder. However, the drag coefficient of the bionic rudder is markedly lower than that of the unmodified rudder. Therefore, the lift-to-drag ratio of the bionic rudder is obviously higher than the unmodified rudder. In another case of Re = 8 × 105, the advantageous behavior of the bionic rudder with leading-edge protuberances is mainly performed in the post-stall regime. The flow mechanism of the significantly increased efficiency by the protuberant leading-edge is explored. It is obvious that the pairs of counter-rotating vortices are presented over the suction surface of bionic rudder, and therefore, the flow is more likely to adhere to the suction surface of bionic rudder.

Design and Numerical Investigation of Rudder With Leading-Edge Protuberances

2018 ◽  
Author(s):  
Wencai Zhu ◽  
Hongtao Gao
Keyword(s):  
Numerical Investigation ◽  
Turbulence Model ◽  
Lift Coefficient ◽  
Pressure Coefficient ◽  
Leading Edge ◽  
Numerical Results ◽  
Spanwise Direction ◽  
Suction Surface ◽  
Pressure Surface ◽  
Edge Profile

The marine rudder with leading-edge protuberances is numerically investigated by SST k-ω turbulence model in present investigations. The newly designed rudder has a sinusoidal leading-edge profile along the spanwise direction. The numerical results show that the newly designed rudder helps to improve the lift coefficient of the rudder. The efficiency of the rudder is improved by adopting the leading-edge protuberances. The results are analyzed by means of streamlines and pressure coefficient. The leading-edge protuberances can delay or overcome the stall. The effect of leading-edge protuberances on the pressure coefficient of pressure surface is very small. However, the pressure coefficient of the suction surface is changed in the vicinity of leading-edge.

An Investigation Into Improving Off-Design Performance in a Turbocharger Turbine Utilizing Non-Radial Blading

2011 ◽  
Author(s):  
Jason Walkingshaw ◽  
Stephen Spence ◽  
Jan Ehrhard ◽  
David Thornhill
Keyword(s):  
Negative Impact ◽  
Leading Edge ◽  
Vital Role ◽  
Secondary Flows ◽  
Blade Angle ◽  
Suction Surface ◽  
Design Point ◽  
Design Performance ◽  
Edge Profile ◽  
Inlet Angle

Off-design performance now plays a vital role in the design decisions made for automotive turbocharger turbines. Of particular interest is extracting more energy at high pressure ratios and lower rotational speeds. In this region of operation the U/C value will be low and the rotor will experience high values of positive incidence at the inlet. The positive incidence causes flow to separate on the suction surface and produces high blade loading at inlet, which drives tip leakage. A CFD analysis has been carried out on a number of automotive turbines utilizing non-radial fibred blading. To help improve secondary flows yet meet stress requirements a number of designs have been investigated. The inlet blade angle has been modified in a number of ways. Firstly, the blading has been adjusted as to provide a constant back swept angle in the span wise direction. Using the results of the constant back swept blading studies, the back swept blade angle was then varied in the span wise direction. In addition to this, in an attempt to avoid an increase in stress, the effect of varying the leading edge profile of the blade was investigated. It has been seen that off-design performance is improved by implementing back swept blading at the inlet. Varying the inlet angle in the span wise direction provided more freedom for meeting stress requirements and reduces the negative impact on blade performance at the design point. The blade leading edge profile was seen to offer small improvements during off-design operation with minimal effects on stress within the rotor. However, due to the more pointed nature of the leading edge, the rotor was less tolerant to flow misalignment at the design point.

scholarly journals On the reduction of aerofoil–turbulence interaction noise associated with wavy leading edges

2016 ◽  
Vol 792 ◽  
pp. 526-552 ◽  
Author(s):  
Jae Wook Kim ◽  
Sina Haeri ◽  
Phillip F. Joseph
Keyword(s):  
Noise Reduction ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Leading Edge ◽  
Mean Flow ◽  
Frequency Spectra ◽  
Phase Interference ◽  
Edge Profile ◽  
Leading Edges ◽  
The Hill

An aerofoil leading-edge profile based on wavy (sinusoidal) protuberances/tubercles is investigated to understand the mechanisms by which they are able to reduce the noise produced through the interaction with turbulent mean flow. Numerical simulations are performed for non-lifting flat-plate aerofoils with straight and wavy leading edges (denoted by SLE and WLE, respectively) subjected to impinging turbulence that is synthetically generated in the upstream zone (free-stream Mach number of 0.24). Full three-dimensional Euler (inviscid) solutions are computed for this study thereby eliminating self-noise components. A high-order accurate finite-difference method and artefact-free boundary conditions are used in the current simulations. Various statistical analysis methods, including frequency spectra, are implemented to aid the understanding of the noise-reduction mechanisms. It is found with WLEs, unlike the SLE, that the surface pressure fluctuations along the leading edge exhibit a significant source-cutoff effect due to geometric obliqueness which leads to reduced levels of radiated sound pressure. It is also found that there exists a phase interference effect particularly prevalent between the peak and the hill centre of the WLE geometry, which contributes to the noise reduction in the mid- to high-frequency range.

Hydrodynamic Performance of Leading-Edge Tubercle Three-Dimensional Airfoil

2012 ◽  
Vol 152-154 ◽  
pp. 1509-1515 ◽  
Author(s):  
Feng Feng ◽  
Xiang Ru Cheng ◽  
Xiang Yang Qi ◽  
Xin Chang
Keyword(s):  
Numerical Simulation ◽  
Research Method ◽  
Optimization Design ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Leading Edge ◽  
Hydrodynamic Performance ◽  
Normal Model ◽  
Edge Profile ◽  
Calculation Results

Based on RANS method, this paper studied leading-edge tubercle three-dimensional airfoil, which had effect on hydrodynamic performance of three-dimensional airfoil. Both section configurations of the two three-dimensional airfoil models were NACA0020 airfoil. The research method was numerical simulation. First, the leading-edge profile of the first airfoil model was normal. To get stalling angle of the first model, it analyzed hydrodynamic performance of the first model under different angle of attacks at Re=1.35*105. Then, the second model had a sinusoidal leading-edge profile. The second model chose the same Reynolds number. By comparison the numerical calculation results between the first and the second model, the stalling angle of second model delays 3°than the normal airfoil, and the lift coefficient of the second model increases 11.92% than the normal model. The results have laid the foundation for optimization design of leading-edge tubercle three-dimensional airfoil.

Numerical Investigation on the Aerodynamic Performance of an Airfoil With Leading-Edge Protuberances

2016 ◽  
Author(s):  
Chang Cai ◽  
Zhigang Zuo ◽  
Shuhong Liu
Keyword(s):  
Control Method ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Streamwise Vortex ◽  
Hydrodynamic Performance ◽  
Small Range ◽  
Wide Range ◽  
Edge Profile ◽  
Passive Technique ◽  
Stall Angle

Leading edge protuberance modifications on airfoils or wings have attracted extensive attentions as a new passive technique for separation control. In this paper, the hydrodynamic performance of a NACA 634-021 foil and a modified foil with leading-edge protuberances were numerically investigated using Spalart-Allmaras turbulence model. Compared to the sharp decline of baseline lift coefficient, the stall angle of the modified foils was advanced and the decline of lift coefficient became mild, and the post-stall performance was improved. A special bi-periodic flow pattern may occur and stay extremely steady at a wide range of attack angles, accompanied with a relatively steady lift. The transformation from single-periodicity to bi-periodicity occurred within a small range of range of attack angle. A couple of counter-rotating streamwise vortex was formed on the shoulder of each protuberance, altering the vorticity line to share a similar shape as the leading-edge profile. At larger angles of attack, the development of streamwise vortex would be accompanied with transformation to lateral vortex, where strong interaction may happen and give rise to the occurrence of bi-periodic condition. The formation mechanism and control method of the special phenomenon should be investigated more deeply in the future.

SOFT BODY IMPACT SIMULATION ON COMPOSITE STRUCTURES

2008 ◽  
Vol 32 (2) ◽  
pp. 283-296 ◽  
Author(s):  
M. Nejad Ensan ◽  
D.G. Zimcik ◽  
M. Lahoubi ◽  
D. Andrieu
Keyword(s):  
Composite Structures ◽  
Impact Load ◽  
Impact Damage ◽  
Leading Edge ◽  
Soft Body ◽  
Local Pressure ◽  
Edge Structure ◽  
Wing Structures ◽  
The Impact ◽  
Composite Wing

The paper describes recent progress on numerical simulation of soft body impact onto a fibre reinforced composite wing leading edge structure. The work is based on the application of non-linear explicit finite element analysis to simulate the response of composite wing structures under soft body impact loads. Soft body impactors such as gelatine (substitute bird) or ice (hailstones) are highly deformable on impact and flow over the structure spreading the impact load. Therefore, first benchmark simulations were carried out for soft body impact onto a rigid target. Soft body impactor was modeled using the Arbitrary Lagrangian-Eulerian (ALE) method. The results obtained using this impact model for different velocity were compared to the experimental test results in terms of local pressure, including Hugoniot and stagnation pressures, and global load to validate the accuracy of the model. Then, the impact of soft body onto a composite wing structures was described. A composite failure model which includes ply damage and interplay delamination model has been used to predict impact damage in the structure modeled using shell elements. The simulation tool predicts the impact damage in leading edge structure.

The effect of leading-edge profile on self-induced oscillation of 45-degree delta wings

2000 ◽  
Author(s):  
Takashi Matsuno ◽  
Shigeru Yokouchi ◽  
Yoshiaki Nakamura
Keyword(s):  
Leading Edge ◽  
Delta Wings ◽  
Edge Profile
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